The U.S.-based website 38 North, which monitors North Korea, said that commercial satellite imagery from August indicated only low levels of activity at the Yongbyon Nuclear Scientific Research Center with no signs of reactor operations.  

The report released on Friday said that vehicles were observed near the five megawatts electric reactor with at least four and perhaps five seen on the road east of the reactor on August fourth but that by the 13th, just two vehicles remained in the area.

38 North noted that between the fourth and 13th, imagery indicated that several objects had arrived on the road next to the Experimental Light Water Reactor(ELWR), but that the purpose of the objects remain unclear.

According to the report, construction is continuing on the engineering office building west of the ELWR and tarps covered two large objects on the parking apron in front of the building, which are likely for interior work as the building appears to be externally complete.  

The website said the newly occupied buildings associated with the Radioisotope Production Plant near the Uranium Enrichment Plant also appeared to be operational, while vehicles and unidentified equipment were present on August 25th.

It said that while the function of the buildings is not known, they are connected by conduit to the Radioisotope Production Plant and could be associated with the production of uranium hexafluoride.

Meanwhile on the Kyurong River next to the nuclear facilities, satellite imagery indicated the sluiceway was wide open by August 25th as water continued to overtop the dam amid the rising river level from Monsoon rains.

South Korea's National Intelligence Service said earlier this year that it believes the five megawatts reactor was suspended last year while the uranium enrichment facility is known to be operating.